Positive displacement pumps are used in, for example, the semiconductor manufacturing industry for the purpose of dispensing high-purity process fluids such as corrosive and/or caustic process fluids for semiconductor processing. In such application, it is important that the volume of the process fluid being dispensed be accurate, that the accuracy of fluid dispensement be consistent. It is also important that the process fluid being dispensed be done in a manner that maintains its high level of purity. Accordingly, it is important that pumps placed into such service not introduce contaminant matter that can be transferred downstream, which could eventually damage or contaminate the high-purity finished product, e.g., semiconductors and the like.
These high purity process fluids are oftentimes heated to temperatures near their boiling point to increase their efficiency in performing the particular semiconductor manufacturing process. Accordingly, it is important that dispense pumps placed into service with such process fluids be capable of dispensing such corrosive and/or caustic process fluids under high-temperature conditions without failing.
Conventional pumps that may be used for dispensing process fluids in such application include syringe pumps and peristaltic pumps. Typically, syringe pumps that may be used in this type of application are not acceptable for at least two reasons. First, the seal in a syringe pump is known to be the source of a percentage of leakage. Such leakage is not desired due both to the possibility of inaccurate fluid dispensement, and due to the possibility of safety issues due to the aggressive nature of the process fluids being dispensed should they be allowed to escape into the workplace environment. Additionally, the seal in the syringe pump is a dynamic member that is known to become worn during use. The wearing of such seal would be the source of unwanted particle generation that would introduce unwanted contaminate particles into the process fluid.
Peristaltic pumps that are typically used in such application are also known to have significant particle generation issues, as well as not being able to consistently provide a desired dispensement accuracy at the levels required by the industry.
It is, therefore, desired that a pump be constructed that is capable of consistently dispensing extremely accurate quantities of fluids, such as those used in the semiconductor manufacturing industry. It is further desired that such pumps be constructed in a manner that facilitates such accurate fluid dispensement in a manner that is repeatable and/or continuous. It is also desired that such pumps be constructed to do this in a manner that maintains the high-purity nature of the fluid being dispensed, without introducing contaminate material therein. Finally, it is desired that such pumps be constructed to do this without presenting leakage issues that could adversely impact accurate fluid dispensement and/or allow any such process fluid leakage to present a safety issue.